The present invention relates to a vehicular lamp and to an injection mold and manufacturing method for a lamp body of the same.
Many types of vehicular lamps such as a rear fog lamp and a tail lamp are configured such that the lamp body thereof includes a reflective surface for reflecting light from a light source bulb forward, and the lamp body is formed with a bulb attachment hole for mounting the light source bulb to the lamp body.
These lamps can vary in light distribution performance depending on the type of lamp even though their appearance may be the same. Therefore, lamp bodies with various shapes of the reflective surface and the bulb attachment hole must be manufactured in accordance with the type of lamp.
A lamp body is typically constituted by an injection molded product. The need for manufacturing a different lamp body for each type of lamp requires a plurality of types of injection molds, which is a major factor in increasing the cost of manufacturing such lamps.
It is possible to use a common lamp body if the lamp body is configured such that a separate reflector can be attached to the reflective surface of the lamp body, in which case the choice of whether or not to provide the reflector is made depending on the type of lamp. For example, when a lamp body which has been designed for a tail lamp is carried over to a rear fog lamp, it is possible to use the same lamp body for a rear fog lamp by attaching a suitable reflector to the reflective surface of the lamp body.
According to this arrangement, however, a different reflector is required depending on the type of lamp, which causes an increase in the number of parts and results in a problem of increased lamp cost.
Considering the foregoing, it is an object of the present invention to provide a vehicular lamp, and an injection mold for a lamp body and a manufacturing method for the same, whereby, when manufacturing a lamp body for a plurality of types of lamps by injection molding, the cost of manufacturing the lamps is reduced by employing a common injection mold.
The present invention aims to accomplish the aforementioned object with a configuration such that a part of a reflective surface is molded with a cavity surface of an insert.
More specifically, a vehicular lamp according to the present invention includes a light source bulb, a lamp body including a reflective surface for reflecting light from the light source bulb forward and being formed with a bulb attachment hole for mounting the light source bulb to the lamp body, and a translucent cover attached to the lamp body so as to form a lamp chamber with the lamp body, wherein the lamp body is constituted by an injection molded product, and a part of the reflective surface of the lamp is constituted by an insert-molded surface molded with a cavity surface of an insert constituting a part of a fixed mold or a movable mold of an injection mold.
Further, an injection mold for a lamp body according to the present invention, which is intended for use in manufacturing by injection molding a lamp body of a vehicular lamp including a reflective surface for reflecting light from a light source bulb forward and being formed with a bulb attachment hole for attaching the light source bulb, is characterized in that one of a fixed mold and a movable mold for forming a cavity with a shape corresponding to the lamp body is constituted by a mold body and an insert detachably attached to the mold body, and a part of the reflective surface is molded by the cavity surface of the insert.
Still further, a method according to the present invention for manufacturing a lamp body by injection molding a lamp body of a vehicular lamp including a reflective surface for reflecting a light from the light source bulb forward and being formed with a bulb attachment hole for attaching the light source bulb, is characterized in that one of a fixed mold and a movable mold for forming a cavity with a shape corresponding to the lamp body is configured such that the insert is detachably attached to the mold body, and a part of the reflective surface is molded by the cavity surface of the insert.
The type of vehicular lamp to which the invention may be applied is not particularly limited, and can be, for example, a rear fog lamp, a tail lamp, a tail and stop lamp, a turn signal lamp, a cornering lamp, a clearance lamp, a fog lamp, a driving lamp, or a headlamp, or the like.
The aforementioned reflective surface may be constituted by a single curved surface, a plurality of curved surfaces smoothly connected with each other, or a plurality of reflective elements.
In addition, the alignment, shape, size and the like of the aforementioned part of the reflective surface is not particularly limited.
The translucent cover may be a plain one, a cover on which lens elements are formed, or a colorless or colored cover.
A vehicular lamp according to the present invention is configured such that the lamp body thereof is constituted by an injection molded product which includes a reflective surface for reflecting light from a light source bulb forward and is formed with a bulb attachment hole for attaching the light source bulb. Because a part of the reflective surface of the lamp body is constituted by an insert-molded surface molded by a cavity surface of the insert constituting a part of a fixed mold or a movable mold of an injection mold, the following advantageous effects can be obtained.
Namely, if injection molding is performed using inserts with different cavity surface shapes, it is possible to manufacture a lamp body with partially different reflection surface shapes while sharing a common main structure for the injection mold. This enables a plurality of types of lamp bodies with different light distribution performance to be obtained.
Therefore, by preparing a plurality of types of inserts having a cavity surface with a predetermined shape corresponding to the light distribution performance of the lamp, and performing injection molding by switching the insert depending on the type of lamp, a plurality of types of lamp bodies can be obtained corresponding to a desired light distribution performance of the lamp without the need to provide a separate reflector for each type of lamp, as in a conventional case.
Accordingly, when manufacturing a plurality of types of lamp bodies by injection molding, the present invention can reduce the cost of manufacturing a lamp by using a common injection mold, and consequently can reduce the cost of a lamp by eliminating the necessity to increase the number of parts.
Moreover, if the bulb attachment hole is also constituted by the insert-molded surface, it is possible to easily mount different types of light source bulbs corresponding to the light distribution performance of the lamp. Further, because a protruding portion is formed on the insert, it is possible to easily attach and detach the insert.
In the aforementioned configuration, if a reflective surface of the lamp body is constituted by a plurality of reflective elements, the following effects can be obtained.
Namely, when the reflective surface of the lamp is constituted by smooth curved surfaces, if only the shape of the insert-molded surface is changed, the thickness of the lamp body will be greatly changed in part from a basic thickness. As a result, shrinkage is likely to occur on the reflective surface, or the flowability of the molten resin is likely to decrease during injection molding.
On the contrary, when the reflective surface of the lamp body is constituted by a plurality of reflective elements, when only the shape of the insert-molded surface is changed, the change in shape occurs in each reflective element, preventing the basic thickness from being greatly changed. Therefore, the occurrence of shrinkage in the reflective surface or a decrease in the flowability of the molten resin during injection molding can be effectively reduced.
Moreover, if the position of the boundary between the insert-molded surface and other parts of the reflective surface is substantially the same as the position of the boundary between the various reflective elements, the profile of the insert formed on the reflective surface by injection molding can be made less conspicuous.
Further, in this configuration, if the translucent cover is constituted by a red-colored translucent cover and the lamp is a rear fog lamp, a tail lamp, or a tail and stop lamp that is designed to emit red light, the light distribution performance for each lamp can be easily ensured by switching the insert based on the use of a common translucent cover.